This study was performed to investigate the feasibilities, characteristics and mechanisms of laser bonding heterogeneous joints from thermoset carbon fiber reinforced sheet molding compound (SMC) and dual-phase steel (DP590) with the aid of an intermediate polycarbonate (PC) mid-layer. The single lap-joint showed that the load at failure reached up to 3.31 kN (i.e. 4.9 MPa for shear strength). Morphological analysis of four fracture modes as well as mechanical characterization of the heterogeneous joints were carried out to understand the effect of laser line energy on the joint quality including defects and strength. By analyzing the relationship between the area percentage of four fracture modes and ultimate shear force (USF) of the joints with various line energies, the contribution of each fracture mode to the joint strength was determined and discussed. In addition, cross-sectional analysis indicates that bubble expansion caused by SMC substrate degradation results in carbon fibers being squeezed into molten PC, which increases the bonding area by creating wavy contacts and generates a mechanical interlock at the SMC/PC interface.

进行这项研究的目的是借助中间聚碳酸酯（PC）来研究热固性碳纤维增强片状模塑料（SMC）和双相钢（DP590）对异种接头进行激光粘合的可行性，特性和机理。单个搭接接头显示出破坏时的载荷高达3.31 kN（即剪切强度为4.9 MPa）。为了了解激光线能量对接头质量（包括缺陷和强度）的影响，对四种断裂模式进行了形态分析，并对异质接头进行了机械表征。通过分析四种断裂模式的面积百分比与各种线能量的接头的极限剪切力（USF）之间的关系，确定并讨论了每种断裂模式对接头强度的贡献。此外，横截面分析表明，由SMC基材降解引起的气泡膨胀会导致碳纤维被挤压到熔融PC中，从而通过形成波浪状接触而增加粘结面积，并在SMC / PC界面处产生机械互锁。